PRISMA Space Segment

02.03.2017

ASI, C. Contini

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PRISMA Space Segment

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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PRISMA Mission Overview

PRISMA is a pre-operative mission with the task to deliver hyperspectral and PAN images of

the Earth from specific targets requested by the End Users on the defined AoI.

To this aim the system shall perform the following functions:

images acquisition

downloading of the collected images to ground

processing of the image data

delivery of the products to the End User

PRISMA

Operative modes:

Primary: on-demand collection of specific

Hyp + PAN data

Secondary: ‘background’ task to acquire

images by fully using satellite and downlink

resources

PRISMA / ASI Workshop / 01-03.03.2017

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PRISMA Mission Overview

SUB-SATELLIT

E TRACK

SATELLITE MOTION

SW

ATH

H

SUB-SATELLITE POINT

INSTRUMENT FOV

INSTRUMENT LOS

HEEL

TOE

ACCESS AREA

OFF-NADIR ANGLE

enrico battistelli

PRISMA P/L operates with a Pushbroom scanning

concept that records reflected radiation from the

Earth surface in the

PAN range

visible/near infrared (VNIR) range

short wave infrared (SWIR) range with a band width

of 10 nm.

PAN sensor is characterized by a 5 m GSD

(@nadir/sea level); VNIR/ SWIR GSD is 30 m.

Hyperspectral sensor utilizes prisms to obtain the

dispersion of incoming radiation on a 2-D matrix

detectors, to acquire several spectral bands (239)

of the same strip on ground.

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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Area of Interest

Longitude: 180°W÷180°E

Latitude: 70°S÷70°N

Primary Area of Interest

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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Imaging capability

Capacity to acquire, download, process up to L0a (including quicklook)

and archive all Hyperspectral and Panchromatic channels for a

maximum of 200.000 km2 on a daily basis

Imaging capacity:

Capacity to daily process 200 hyperspectral scenes (30 km x 30 km)

up to level 2d

Target access opportunities over the P-AoI:

duration/day: 240 minutes

number of orbits/day: 15/15

Daily imaging & processing capabilities (Hyp/Pan channels)

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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PRISMA Mission Overview

Mission key parameters related to the

image acquisition:

revisit time capability to observe the

same target twice.

area coverage ability to observe all the

possible targets within the area target

image capacity capability to acquire and

download all the required data

orbit parameters S/N ratio, eclipse period,

ground station contacts duration…

P/L data will be downloaded to CNM

(Matera) by X-band link

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

Orbit SSO 615 km 10:30 LTDN

Revisit time 7 days

AoI 70° Nord ÷ 70° Sud

Max Off-nadir ±21° across track

Onboard Data Storage 448 Gbit

Downlink data rate 310 Mbps

Imaging capacity 200.000 km2/day

Pushbroom, strip ≤ 1800km

Dv 120 m/s

Pointing accuracy < 1 km

Response time < 14 days

( acquisition latency < 9.5 days

processing latency < 4.5 days)

Launch Mid 2018, VEGA LV

Lifetime 5 ys

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PRISMA System Architecture

PRISMA System is made by:

Space Segment: one small Satellite

Ground Segment

Fucino: MCC (Mission Control

Center) / SCC (Satellite Control

Center)

Matera: IDHS (Image Data Handling

System)

Launch Segment: VEGA

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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PRISMA System Architecture

Access to the Users:

The system provides a single interface to the Users for catalogue browsing, acquisition requests and

product ordering:

the IDHS provides catalogue searching functions, manages the request for archived products,

delivers data (through ftp or physical media)

the MCC handles the requests of acquisition of images

Data acquisition procedure:

nominal satellite attitude is sun-pointing (power)

earth-pointing and payload activation over the required area target

data recorded into the PDHT memory and downloaded to the X-Band ground station (CNM, asap)

Telemetry and telecommands:

bi-directional S-band link to a Ground Station located in Fucino

Orbit maintenance:

calculated and planned by the flight dynamics function of the SCC

time tagged telecommands generated by the MCC

TC uploaded to the satellite by the SCC itself

Launch segment:

“small class” dedicated launcher (single launch) to inject the satellite in its final orbit (VEGA).

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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The Spacecraft

The Space Segment consists of a single satellite placed in a

LEO SSO orbit with an operational lifetime of at least 5 years

with nominal performance.

The S/C is composed by:

a Platform

a Payload, consisting in a Hyperspectral / Panchromatic

instrument (derived from HypSEO mission)

a Payload Data Handling and Transmission unit (PDHT)

SOLAR

ARRAY

PAYLOAD

LOWER

MODULE

UPPER

MODULE

SIR

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

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Platform Subsystems

Platform will provide all the resources required by the Payload in order to satisfy the mission objectives.

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

Dimensions 2.17 m x 1.47 m x 3.59 mMass ~ 800 KgSolar array ~ 1320 W EoLPower (average) ~ 450 WPointing accuracy ~ 100 arcsec @ 3s

Pointing knowledge ~ 70 arcsec @ 3s

Off-nadir +/- 21°

TT&C S-band

Propulsion Hydrazine, DV ~ 120 m/sAOCS actuators Reaction wheels

Magneto-torquers

AOCS sensors Sun sensors

Star sensors

Magnetometers

Gyro’s

GPS

LV VEGA

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PRISMA S/C has already accomplished a successful

structural qualification campaign using a new SM model

Compliance to VEGA environmental loads demonstrated:

Sine

Acoustics

Shock (VESTA and drop test)

Main S/C Units EM used for functional and interface

verification (OBDH and P/L ME already tested with PDHT)

S/C PFM will jump into the Acceptance Test Campaign at the

end of 2017

S/C Model Philosophy

PRISMA / ASI Workshop / 01-03.03.2017 PRISMA

OBDH EM S/C SM